Fiber optic communication is an emerging method of transmitting information from a source (transmitter) to a destination (receiver) using optical fibers as the communication channel. Optical fibers are flexible, transparent fibers made of thin glass silica or plastic that transmits light throughout the length of the fiber between the source and the destination. Fiber optic communications allows for the transmission of data over longer distances and at higher bandwidth than other known forms of communications.
High density access equipment, such as an optical line terminal (OLT), for fiber optic communications generally does not have systems that manage temperatures of the equipment in an event of a system fault. The access equipment typically has a basic thermal control system, which is managed by a management control card through an I2C communication bus and protocol. I2C is a simple two wire interface bus allowing multiple masters and slaves to communicate on two signals SCL (serial clock) and SDA (serial data). A multi-master implementation is extremely difficult, so most designs allow only one master. Even in a single master design, there are potential bus contentions, protocol, and timing violations from either the master or slave devices that may cause the bus to become unresponsive.
Some designs try to work around this issue by adding a reset control line to cycle the state of the slave devices. After a reset, any controller cards of the thermal control system require initialization and programming, such as reading system temperatures and reprogramming fan speeds. In the initialization period (dead time), the system can over heat, trigger alarms, and shut down. As OLT equipment becomes more complex, dense in port counts, a system shut down could vastly impact many thousands of users; and repair time could take up to many hours.